Default SM-N900 Modem/ CSC Country question

I had purchased an unlocked sm-n900 because I figured it might be what would work best with my carrier ( Straight Talk) here in the US. Ive had it for a little less than a month now and have had constant connection issues. Today I saw a thread http://forum.xda-developers.com/show....php?t=2475714 In here it is mentioned that

Quote:
Choosing right modem can make a huge difference as it affects reception, data speed, stability, battery life etc.
So I figured I should investigate flashing a new modem and maybe thatll help my situation. The thing is while looking at my phones info I found out the CSC country is Argentina. Does this matter at all? Is this leading to the problems with my phone or is this from the ROM i flashed (CriskeloRom Note III V05) Im just fed up with the constant connection problems and the constant having my phone go into emergency only mode. Where do I go from here? Do I need to flash a different modem, or an entirely different rom? I dont even know if I can flash any of those modems /: Heres some more info I have Latest firmware info

PDA: N900UBUCMK1
CSC: N900UUBCMK1
MODEM: N900UBUCMK1

Can anyone please help
http://fp.profiles.us.playstation.com.s3.amazonaws.com/41/191/vicmora5.png?1294864322863